##// END OF EJS Templates
repair: migrate revlogs during upgrade...
repair: migrate revlogs during upgrade Our next step for in-place upgrade is to migrate store data. Revlogs are the biggest source of data within the store and a store is useless without them, so we implement their migration first. Our strategy for migrating revlogs is to walk the store and call `revlog.clone()` on each revlog. There are some minor complications. Because revlogs have different storage options (e.g. changelog has generaldelta and delta chains disabled), we need to obtain the correct class of revlog so inserted data is encoded properly for its type. Various attempts at implementing progress indicators that didn't lead to frustration from false "it's almost done" indicators were made. I initially used a single progress bar based on number of revlogs. However, this quickly churned through all filelogs, got to 99% then effectively froze at 99.99% when it got to the manifest. So I converted the progress bar to total revision count. This was a little bit better. But the manifest was still significantly slower than filelogs and it took forever to process the last few percent. I then tried both revision/chunk bytes and raw bytes as the denominator. This had the opposite effect: because so much data is in manifests, it would churn through filelogs without showing much progress. When it got to manifests, it would fill in 90+% of the progress bar. I finally gave up having a unified progress bar and instead implemented 3 progress bars: 1 for filelog revisions, 1 for manifest revisions, and 1 for changelog revisions. I added extra messages indicating the total number of revisions of each so users know there are more progress bars coming. I also added extra messages before and after each stage to give extra details about what is happening. Strictly speaking, this isn't necessary. But the numbers are impressive. For example, when converting a non-generaldelta mozilla-central repository, the messages you see are: migrating 2475593 total revisions (1833043 in filelogs, 321156 in manifests, 321394 in changelog) migrating 1.67 GB in store; 2508 GB tracked data migrating 267868 filelogs containing 1833043 revisions (1.09 GB in store; 57.3 GB tracked data) finished migrating 1833043 filelog revisions across 267868 filelogs; change in size: -415776 bytes migrating 1 manifests containing 321156 revisions (518 MB in store; 2451 GB tracked data) That "2508 GB" figure really blew me away. I had no clue that the raw tracked data in mozilla-central was that large. Granted, 2451 GB is in the manifest and "only" 57.3 GB is in filelogs. But still. It's worth noting that gratuitous loading of source revlogs in order to display numbers and progress bars does serve a purpose: it ensures we can open all source revlogs. We don't want to spend several minutes copying revlogs only to encounter a permissions error or similar later. As part of this commit, we also add swapping of the store directory to the upgrade function. After revlogs are converted, we move the old store into the backup directory then move the temporary repo's store into the old store's location. On well-behaved systems, this should be 2 atomic operations and the window of inconsistency show be very narrow. There are still a few improvements to be made to store copying and upgrading. But this commit gets the bulk of the work out of the way.

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branchmap.py
522 lines | 19.9 KiB | text/x-python | PythonLexer
# branchmap.py - logic to computes, maintain and stores branchmap for local repo
#
# Copyright 2005-2007 Matt Mackall <mpm@selenic.com>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
from __future__ import absolute_import
import array
import struct
import time
from .node import (
bin,
hex,
nullid,
nullrev,
)
from . import (
encoding,
error,
scmutil,
)
array = array.array
calcsize = struct.calcsize
pack = struct.pack
unpack = struct.unpack
def _filename(repo):
"""name of a branchcache file for a given repo or repoview"""
filename = "cache/branch2"
if repo.filtername:
filename = '%s-%s' % (filename, repo.filtername)
return filename
def read(repo):
try:
f = repo.vfs(_filename(repo))
lines = f.read().split('\n')
f.close()
except (IOError, OSError):
return None
try:
cachekey = lines.pop(0).split(" ", 2)
last, lrev = cachekey[:2]
last, lrev = bin(last), int(lrev)
filteredhash = None
if len(cachekey) > 2:
filteredhash = bin(cachekey[2])
partial = branchcache(tipnode=last, tiprev=lrev,
filteredhash=filteredhash)
if not partial.validfor(repo):
# invalidate the cache
raise ValueError('tip differs')
cl = repo.changelog
for l in lines:
if not l:
continue
node, state, label = l.split(" ", 2)
if state not in 'oc':
raise ValueError('invalid branch state')
label = encoding.tolocal(label.strip())
node = bin(node)
if not cl.hasnode(node):
raise ValueError('node %s does not exist' % hex(node))
partial.setdefault(label, []).append(node)
if state == 'c':
partial._closednodes.add(node)
except KeyboardInterrupt:
raise
except Exception as inst:
if repo.ui.debugflag:
msg = 'invalid branchheads cache'
if repo.filtername is not None:
msg += ' (%s)' % repo.filtername
msg += ': %s\n'
repo.ui.debug(msg % inst)
partial = None
return partial
### Nearest subset relation
# Nearest subset of filter X is a filter Y so that:
# * Y is included in X,
# * X - Y is as small as possible.
# This create and ordering used for branchmap purpose.
# the ordering may be partial
subsettable = {None: 'visible',
'visible': 'served',
'served': 'immutable',
'immutable': 'base'}
def updatecache(repo):
cl = repo.changelog
filtername = repo.filtername
partial = repo._branchcaches.get(filtername)
revs = []
if partial is None or not partial.validfor(repo):
partial = read(repo)
if partial is None:
subsetname = subsettable.get(filtername)
if subsetname is None:
partial = branchcache()
else:
subset = repo.filtered(subsetname)
partial = subset.branchmap().copy()
extrarevs = subset.changelog.filteredrevs - cl.filteredrevs
revs.extend(r for r in extrarevs if r <= partial.tiprev)
revs.extend(cl.revs(start=partial.tiprev + 1))
if revs:
partial.update(repo, revs)
partial.write(repo)
assert partial.validfor(repo), filtername
repo._branchcaches[repo.filtername] = partial
def replacecache(repo, bm):
"""Replace the branchmap cache for a repo with a branch mapping.
This is likely only called during clone with a branch map from a remote.
"""
rbheads = []
closed = []
for bheads in bm.itervalues():
rbheads.extend(bheads)
for h in bheads:
r = repo.changelog.rev(h)
b, c = repo.changelog.branchinfo(r)
if c:
closed.append(h)
if rbheads:
rtiprev = max((int(repo.changelog.rev(node))
for node in rbheads))
cache = branchcache(bm,
repo[rtiprev].node(),
rtiprev,
closednodes=closed)
# Try to stick it as low as possible
# filter above served are unlikely to be fetch from a clone
for candidate in ('base', 'immutable', 'served'):
rview = repo.filtered(candidate)
if cache.validfor(rview):
repo._branchcaches[candidate] = cache
cache.write(rview)
break
class branchcache(dict):
"""A dict like object that hold branches heads cache.
This cache is used to avoid costly computations to determine all the
branch heads of a repo.
The cache is serialized on disk in the following format:
<tip hex node> <tip rev number> [optional filtered repo hex hash]
<branch head hex node> <open/closed state> <branch name>
<branch head hex node> <open/closed state> <branch name>
...
The first line is used to check if the cache is still valid. If the
branch cache is for a filtered repo view, an optional third hash is
included that hashes the hashes of all filtered revisions.
The open/closed state is represented by a single letter 'o' or 'c'.
This field can be used to avoid changelog reads when determining if a
branch head closes a branch or not.
"""
def __init__(self, entries=(), tipnode=nullid, tiprev=nullrev,
filteredhash=None, closednodes=None):
super(branchcache, self).__init__(entries)
self.tipnode = tipnode
self.tiprev = tiprev
self.filteredhash = filteredhash
# closednodes is a set of nodes that close their branch. If the branch
# cache has been updated, it may contain nodes that are no longer
# heads.
if closednodes is None:
self._closednodes = set()
else:
self._closednodes = closednodes
def validfor(self, repo):
"""Is the cache content valid regarding a repo
- False when cached tipnode is unknown or if we detect a strip.
- True when cache is up to date or a subset of current repo."""
try:
return ((self.tipnode == repo.changelog.node(self.tiprev))
and (self.filteredhash == \
scmutil.filteredhash(repo, self.tiprev)))
except IndexError:
return False
def _branchtip(self, heads):
'''Return tuple with last open head in heads and false,
otherwise return last closed head and true.'''
tip = heads[-1]
closed = True
for h in reversed(heads):
if h not in self._closednodes:
tip = h
closed = False
break
return tip, closed
def branchtip(self, branch):
'''Return the tipmost open head on branch head, otherwise return the
tipmost closed head on branch.
Raise KeyError for unknown branch.'''
return self._branchtip(self[branch])[0]
def branchheads(self, branch, closed=False):
heads = self[branch]
if not closed:
heads = [h for h in heads if h not in self._closednodes]
return heads
def iterbranches(self):
for bn, heads in self.iteritems():
yield (bn, heads) + self._branchtip(heads)
def copy(self):
"""return an deep copy of the branchcache object"""
return branchcache(self, self.tipnode, self.tiprev, self.filteredhash,
self._closednodes)
def write(self, repo):
try:
f = repo.vfs(_filename(repo), "w", atomictemp=True)
cachekey = [hex(self.tipnode), str(self.tiprev)]
if self.filteredhash is not None:
cachekey.append(hex(self.filteredhash))
f.write(" ".join(cachekey) + '\n')
nodecount = 0
for label, nodes in sorted(self.iteritems()):
for node in nodes:
nodecount += 1
if node in self._closednodes:
state = 'c'
else:
state = 'o'
f.write("%s %s %s\n" % (hex(node), state,
encoding.fromlocal(label)))
f.close()
repo.ui.log('branchcache',
'wrote %s branch cache with %d labels and %d nodes\n',
repo.filtername, len(self), nodecount)
except (IOError, OSError, error.Abort) as inst:
repo.ui.debug("couldn't write branch cache: %s\n" % inst)
# Abort may be raise by read only opener
pass
def update(self, repo, revgen):
"""Given a branchhead cache, self, that may have extra nodes or be
missing heads, and a generator of nodes that are strictly a superset of
heads missing, this function updates self to be correct.
"""
starttime = time.time()
cl = repo.changelog
# collect new branch entries
newbranches = {}
getbranchinfo = repo.revbranchcache().branchinfo
for r in revgen:
branch, closesbranch = getbranchinfo(r)
newbranches.setdefault(branch, []).append(r)
if closesbranch:
self._closednodes.add(cl.node(r))
# fetch current topological heads to speed up filtering
topoheads = set(cl.headrevs())
# if older branchheads are reachable from new ones, they aren't
# really branchheads. Note checking parents is insufficient:
# 1 (branch a) -> 2 (branch b) -> 3 (branch a)
for branch, newheadrevs in newbranches.iteritems():
bheads = self.setdefault(branch, [])
bheadset = set(cl.rev(node) for node in bheads)
# This have been tested True on all internal usage of this function.
# run it again in case of doubt
# assert not (set(bheadrevs) & set(newheadrevs))
newheadrevs.sort()
bheadset.update(newheadrevs)
# This prunes out two kinds of heads - heads that are superseded by
# a head in newheadrevs, and newheadrevs that are not heads because
# an existing head is their descendant.
uncertain = bheadset - topoheads
if uncertain:
floorrev = min(uncertain)
ancestors = set(cl.ancestors(newheadrevs, floorrev))
bheadset -= ancestors
bheadrevs = sorted(bheadset)
self[branch] = [cl.node(rev) for rev in bheadrevs]
tiprev = bheadrevs[-1]
if tiprev > self.tiprev:
self.tipnode = cl.node(tiprev)
self.tiprev = tiprev
if not self.validfor(repo):
# cache key are not valid anymore
self.tipnode = nullid
self.tiprev = nullrev
for heads in self.values():
tiprev = max(cl.rev(node) for node in heads)
if tiprev > self.tiprev:
self.tipnode = cl.node(tiprev)
self.tiprev = tiprev
self.filteredhash = scmutil.filteredhash(repo, self.tiprev)
duration = time.time() - starttime
repo.ui.log('branchcache', 'updated %s branch cache in %.4f seconds\n',
repo.filtername, duration)
# Revision branch info cache
_rbcversion = '-v1'
_rbcnames = 'cache/rbc-names' + _rbcversion
_rbcrevs = 'cache/rbc-revs' + _rbcversion
# [4 byte hash prefix][4 byte branch name number with sign bit indicating open]
_rbcrecfmt = '>4sI'
_rbcrecsize = calcsize(_rbcrecfmt)
_rbcnodelen = 4
_rbcbranchidxmask = 0x7fffffff
_rbccloseflag = 0x80000000
class revbranchcache(object):
"""Persistent cache, mapping from revision number to branch name and close.
This is a low level cache, independent of filtering.
Branch names are stored in rbc-names in internal encoding separated by 0.
rbc-names is append-only, and each branch name is only stored once and will
thus have a unique index.
The branch info for each revision is stored in rbc-revs as constant size
records. The whole file is read into memory, but it is only 'parsed' on
demand. The file is usually append-only but will be truncated if repo
modification is detected.
The record for each revision contains the first 4 bytes of the
corresponding node hash, and the record is only used if it still matches.
Even a completely trashed rbc-revs fill thus still give the right result
while converging towards full recovery ... assuming no incorrectly matching
node hashes.
The record also contains 4 bytes where 31 bits contains the index of the
branch and the last bit indicate that it is a branch close commit.
The usage pattern for rbc-revs is thus somewhat similar to 00changelog.i
and will grow with it but be 1/8th of its size.
"""
def __init__(self, repo, readonly=True):
assert repo.filtername is None
self._repo = repo
self._names = [] # branch names in local encoding with static index
self._rbcrevs = array('c') # structs of type _rbcrecfmt
self._rbcsnameslen = 0 # length of names read at _rbcsnameslen
try:
bndata = repo.vfs.read(_rbcnames)
self._rbcsnameslen = len(bndata) # for verification before writing
self._names = [encoding.tolocal(bn) for bn in bndata.split('\0')]
except (IOError, OSError):
if readonly:
# don't try to use cache - fall back to the slow path
self.branchinfo = self._branchinfo
if self._names:
try:
data = repo.vfs.read(_rbcrevs)
self._rbcrevs.fromstring(data)
except (IOError, OSError) as inst:
repo.ui.debug("couldn't read revision branch cache: %s\n" %
inst)
# remember number of good records on disk
self._rbcrevslen = min(len(self._rbcrevs) // _rbcrecsize,
len(repo.changelog))
if self._rbcrevslen == 0:
self._names = []
self._rbcnamescount = len(self._names) # number of names read at
# _rbcsnameslen
self._namesreverse = dict((b, r) for r, b in enumerate(self._names))
def _clear(self):
self._rbcsnameslen = 0
del self._names[:]
self._rbcnamescount = 0
self._namesreverse.clear()
self._rbcrevslen = len(self._repo.changelog)
self._rbcrevs = array('c')
self._rbcrevs.fromstring('\0' * (self._rbcrevslen * _rbcrecsize))
def branchinfo(self, rev):
"""Return branch name and close flag for rev, using and updating
persistent cache."""
changelog = self._repo.changelog
rbcrevidx = rev * _rbcrecsize
# avoid negative index, changelog.read(nullrev) is fast without cache
if rev == nullrev:
return changelog.branchinfo(rev)
# if requested rev isn't allocated, grow and cache the rev info
if len(self._rbcrevs) < rbcrevidx + _rbcrecsize:
return self._branchinfo(rev)
# fast path: extract data from cache, use it if node is matching
reponode = changelog.node(rev)[:_rbcnodelen]
cachenode, branchidx = unpack(
_rbcrecfmt, buffer(self._rbcrevs, rbcrevidx, _rbcrecsize))
close = bool(branchidx & _rbccloseflag)
if close:
branchidx &= _rbcbranchidxmask
if cachenode == '\0\0\0\0':
pass
elif cachenode == reponode:
try:
return self._names[branchidx], close
except IndexError:
# recover from invalid reference to unknown branch
self._repo.ui.debug("referenced branch names not found"
" - rebuilding revision branch cache from scratch\n")
self._clear()
else:
# rev/node map has changed, invalidate the cache from here up
self._repo.ui.debug("history modification detected - truncating "
"revision branch cache to revision %s\n" % rev)
truncate = rbcrevidx + _rbcrecsize
del self._rbcrevs[truncate:]
self._rbcrevslen = min(self._rbcrevslen, truncate)
# fall back to slow path and make sure it will be written to disk
return self._branchinfo(rev)
def _branchinfo(self, rev):
"""Retrieve branch info from changelog and update _rbcrevs"""
changelog = self._repo.changelog
b, close = changelog.branchinfo(rev)
if b in self._namesreverse:
branchidx = self._namesreverse[b]
else:
branchidx = len(self._names)
self._names.append(b)
self._namesreverse[b] = branchidx
reponode = changelog.node(rev)
if close:
branchidx |= _rbccloseflag
self._setcachedata(rev, reponode, branchidx)
return b, close
def _setcachedata(self, rev, node, branchidx):
"""Writes the node's branch data to the in-memory cache data."""
rbcrevidx = rev * _rbcrecsize
rec = array('c')
rec.fromstring(pack(_rbcrecfmt, node, branchidx))
if len(self._rbcrevs) < rbcrevidx + _rbcrecsize:
self._rbcrevs.extend('\0' *
(len(self._repo.changelog) * _rbcrecsize -
len(self._rbcrevs)))
self._rbcrevs[rbcrevidx:rbcrevidx + _rbcrecsize] = rec
self._rbcrevslen = min(self._rbcrevslen, rev)
tr = self._repo.currenttransaction()
if tr:
tr.addfinalize('write-revbranchcache', self.write)
def write(self, tr=None):
"""Save branch cache if it is dirty."""
repo = self._repo
wlock = None
step = ''
try:
if self._rbcnamescount < len(self._names):
step = ' names'
wlock = repo.wlock(wait=False)
if self._rbcnamescount != 0:
f = repo.vfs.open(_rbcnames, 'ab')
if f.tell() == self._rbcsnameslen:
f.write('\0')
else:
f.close()
repo.ui.debug("%s changed - rewriting it\n" % _rbcnames)
self._rbcnamescount = 0
self._rbcrevslen = 0
if self._rbcnamescount == 0:
# before rewriting names, make sure references are removed
repo.vfs.unlinkpath(_rbcrevs, ignoremissing=True)
f = repo.vfs.open(_rbcnames, 'wb')
f.write('\0'.join(encoding.fromlocal(b)
for b in self._names[self._rbcnamescount:]))
self._rbcsnameslen = f.tell()
f.close()
self._rbcnamescount = len(self._names)
start = self._rbcrevslen * _rbcrecsize
if start != len(self._rbcrevs):
step = ''
if wlock is None:
wlock = repo.wlock(wait=False)
revs = min(len(repo.changelog),
len(self._rbcrevs) // _rbcrecsize)
f = repo.vfs.open(_rbcrevs, 'ab')
if f.tell() != start:
repo.ui.debug("truncating %s to %s\n" % (_rbcrevs, start))
f.seek(start)
if f.tell() != start:
start = 0
f.seek(start)
f.truncate()
end = revs * _rbcrecsize
f.write(self._rbcrevs[start:end])
f.close()
self._rbcrevslen = revs
except (IOError, OSError, error.Abort, error.LockError) as inst:
repo.ui.debug("couldn't write revision branch cache%s: %s\n"
% (step, inst))
finally:
if wlock is not None:
wlock.release()